For what it's worth, and as you've probably guessed, I do have another
version installation of openmpi.
In fact two, one with the system gcc/gfortran4.2, and one with a locally
compiled gcc/gfortran4.4 .
These both work correctly. The second installation seems to be
interfering with my current attempt,
even though I exported all environment variables I can think of to point
to sun compilers & libraries first,
before configure & compile.